The invention relates to a device for heating weather masts on wind turbines.
On wind turbines different types of anemometers and tail vanes for the determination of the wind speed and wind direction. These are fixed to weather masts which are usually situated on the roof of the wind turbine nacelle. The weather masts each consist of a stand and a lightning protective cage which surrounds the sensors mounted on the weather mast for the protection from lightning stroke. Under certain meteorological conditions, in particular between 0 and −10° C., the external components of wind turbines such as wind sensors and weather masts are icing up. This can result in undesirably high mechanical loads and in inaccuracies of the measurements.
Herein, the counter actions such as the heated wind sensors described in DE 202006000816 U1 are of limited use since the lightning protective cages of the weather masts are icing up as well. Due to this ice build-up the flow conditions on the wind sensor are changed whereby the measured values become highly inaccurate.
Experience has shown that the renouncement of an encapsulating lightning protective cage (Faraday cage) results in damage of the wind sensors due to a lightning stroke.
In EP 2154364 A1, is disclosed a wind turbine in which a cooling air outlet of the nacelle is directed toward the anemometers and thus the excess heat of the rotor is to provide for warming the environmental air of the anemometers. The drawback of this solution is that an undisturbed wind measurement will be impaired by the flow of outlet air resulting in inaccuracies of the measuring results, in particular of the measurement of the wind direction.
DE 2916504 B1 discloses cup stars for anemometers or wind turbines for power generation which comprise simple heating devices, such as e.g. foils, wires or ribbons in the cup.